1. Field of the Invention
The present invention relates to a method and an apparatus in which a timing control is performed in a flat panel display system which utilizes a red-green-blue strip-type plasma display panel.
2. Description of the Prior Art
Currently, as television sets (hereinafter, referred to as "TV") have become more widely used, consumers are demanding slim display apparatuses which have wide screens and which are easily installable. In view of consumers' needs, the existing cathode ray tube (referred to as "CRT") has started to reveal limitations thereof. Thus, the existing display equipment such as the CRT has come to be replaced by a so-called flat panel display (hereinafter, referred to as "FPD") apparatus that has a wide display area and that is slim as well. Further, recently, research projects therein are in progress enthusiastically at home and abroad.
This kind of the FPD device is largely divided into an emissive device and a non-emissive device. The emissive device is usually called an active emitting device and is a device which emits a light by itself. Representative examples of the emissive device are a field emission display (referred to as "FED") device, a vacuum fluorescent display (referred to as "VFD") type device, an electro-luminescence (referred to as "EL") type device, a plasma display panel (hereinafter, referred to as "PDP") and the like. The non-emissive device is called a passive light emitting device, and representative examples of the non-emissive device are a liquid crystal display (referred to as "LCD") device, an electro-chromic display (referred to as "ECD"), an electro-phoretic display (referred to as "EPID") and the like.
Currently, the LCD device occupies the main stream in products such as desk clocks, calculators, lap-tops and the like. However, when this device is adopted to television sets having the screen size of 21 inches and over, it also shows the limitations up to now due to problems in a manufacturing process of a panel and in obtaining an acceptable product. Further, it has the disadvantages of having a narrow visual field angle and of having a response rate which is subject to a temperature variation. Recently, the PDP is newly attracting public attention as the flat panel display of the next generation which is capable of solving the problems of the LCD device.
Because the PDP emits a light by itself in a principle which is similar to that of a fluorescent lamp, it has a uniform brightness and a high contrast although a screen area is as wide as the screen area of the CRT. In addition, the PDP has a visual field angle of 140 degrees and above, and is well-known as the best wide screen display device which has a screen size of 21 to 55 inches. The panel manufacturing process of the PDP is simplified as compared with that of the LCD device and thereby saves a manufacturing cost. However, because the manufacturing cost of the PDP is more than that of the CRT, manufacturers are carrying out searches to reduce the manufacturing cost.
The plasma display is largely classified into a direct current (referred to as "DC") type and an alternating current (referred to as "AC") type according to a structural difference of a discharge cell thereof and a form of a driving voltage based on the structural difference. The DC type is driven by a DC voltage, whereas the AC type is driven by a sinusoidal AC voltage or by a pulse voltage. The AC type includes such a structure that a dielectric layer covers an electrode to serve as a current regulation resistor, whereas the DC type includes such a structure that an electrode is exposed to a discharge room as it is and that a discharge current comes to flow during a supply of the discharge voltage. Because the AC type has the electrode which is covered with the dielectric, it is more durable than the DC type. The AC type has a further advantage in that a wall charge which is generated on a surface of the dielectric as a result of a polarization, causes the cell to have a memory function therein, and is more applicable in the field of display devices than the others.
A color PDP includes a structure of 3 terminals wherein a special electrode is installed in order to improve discharge characteristics thereof. Namely, the 3-terminal structure comprises 3 electrodes per unit cell for display which are an address electrode for entering data, a maintenance electrode for sequentially scanning a line and for maintaining a cell discharge, and a bus electrode for helping a discharge maintenance.
A number of the address electrode for entering data is determined in accordance to a horizontal resolution. For example, in the case where a number of samples per line is 853 for each of the red, green and blue colors, a total number of the samples comes to 2559. Therefore, a required number of the address electrodes is also 2559. In the case where an arrangement of the address electrode has a strip form, red, green and blue electrodes are arranged repeatedly.
As described above, because a circuit arrangement of an electrode driving section is restricted considering a space utilization when thousands the address electrodes are arranged on one side, an upper and lower electrode driving system is adapted wherein the section for driving 1280 electrodes, which are ordered in an odd-numbered sequence, are arranged at an upper end portion of a panel whereas the section for driving 1279 electrodes, which are ordered in an even-numbered sequence, are arranged at a lower end portion thereof (refer to U.S. Pat. No. 4,695,838).
Meanwhile, in order to display a TV signal of a system of national television system committee (hereinafter, referred to as "NTSC") on the PDP, a data processing section converts an interlaced scanning system into a sequential scanning system, and also converts data into data of a subfield system for a PDP contrast processing. Further, the data processing section provides 1280 red-green-blue (hereinafter, referred to as "RGB") pixel data per line to the electrode driving section for driving the upper and lower address electrodes of the panel of the PDP in harmony with the arrangement of the address electrode.
Conventionally, a video data processing section of the PDP comprises a data rearranging section for rearranging digital RGB sample data into subfield data for a contrast processing, a frame memory section for converting one scanning system into the other, a data interfacing section, and a timing control section.
In order to control the timing of respective parts of the video data processing section, the timing control section frequency-demultiplies a main clock and generates timing control signals of the respective parts.
Generally, in order to display a contrast in the PDP, every field is divided into a plurality of subfields which are utilized for displaying pixel data, and the respective subfields are driven by steps which are divided into an entry and elimination of a whole pixel, an entry of data and a maintenance of a discharge. Therefore, as 2559 pixel data has to be processed for a very short time, i.e., 3 [.mu.s], per scan line, a frequency of a main clock of a system becomes very high. Namely, in the case where a resolution of the PDP is 3.times.853.times.480, the frequency of the main clock of approximate 50 [MHz] is necessary for processing the data. Then, the timing control section counts pulses by 50 [MHz] during one vertical period, and generates various timing control signals. For example, since one vertical period corresponds to 16.67 [ms] in the case of the NTSC, a twenty-bit counter is necessary for counting the pulses in a frequency of 50 [MHz].
However, when such a counter having many bit numbers is utilized, because an output of an upper bit position has a lot of skews generated therein as compared with that of a lower bit position, problems, such as glitches occurring during a decoding operation of the output values, are caused. Also, in the case where all of the outputs are intended to be synchronized with each other in order to solve the noise problems, the design of the counters becomes complicated.